I have these small questions Why Sitemap Reqired? Which site map is usfull to for the site; Html, Xml etc.
A sitemap file helps the search bots find pages that have been ignored or may not normally get crawled.

The HTML sitemap is for your website  visitors.  It is designed to save you some work while it helps visitors find other sections of your website.

The sitemap.xml file is used by the bots from Google, Yahoo, Microsoft Live Search and Ask.com.
Join the xml-sitemaps affiliate program and get paid for sales referrals -


html sitemap is also good inernal linked subpage. For robots its some kind of web with links. This links are internal also this subpage isn't farm of links for Google.